Americans will never forget the terrorist attack on september 11, 2001. one commentator remarked that the force of the explosion at the twin towers of the world trade center was strong enough to blow glass and parts of the steel structure to small fragments. yet the television coverage showed thousands of sheets of paper floating down, many still intact. explain how that could be.

In the twin tower attacks of September 2001, glass and parts of the steel structure were blown away while many could actually see paper floating around.
This boils down to simple physics.

Glass and Steel are fare more stronger than paper itself, however, they are also less flexible. This means, it is more difficult for them to sustain shock and hard force for a long period of time.

Simply compare the difference between dropping a glass to the floor vs dropping a paper to the floor.

Also, since paper can be lighter, it is easy for it to bend and be blown away by force.